Hello Does anyone know how fast the normal counters that are inputs in the micrologix 1200 can go. I am looking for a counting rate of about 600-700Hz. Will I need a high speed counter to accomplish this or can I do it with a 1200 or a 1000 that I have sitting around.

I have a panel view screen that I am going to use to display the counts and thats it.

thanks

Bill

Yes, you definitely need a HSC for 600Hz.

The micrologix 1000 or 1200 built in High Speed Counter will work fine

The micrologix 1200 High Speed Counter can count at 20kHz.
The micrologix 1000 High Speed Counter can count at 6.6 kHz.

So for 600 Hz either should work fine but I would go with the 1200. It cost a little more but gives you much more capability.

Remember to lower the input filters on the High Speed Counter inputs(0 and 1) to there lowest setting or they will not count

Do you know how to setup the High Speed Counter Function file?

You didn't mention the part numbers of the Micrologix you have. I forgot to state that I believe only do DC input Micrologix has the High Speed Counters

Thank you for the reply!

Here is what I am trying to do. I need to count four flow meters for testing and the max speed can get up to 600Hz. I need four high speed counters. I was thinking of using the Micrologix 1500 with the HSC add on as well. I want to hook this up to a panel meter to display the number of counts that occur up until the scale I have on the tank reads 100 gallons sends a signal to the PLC to kick the solenods off.

I have never used the panel view before but I am thinking it will lessen the amount of wiring I will have to do and help the user operate it better. Does ModBus mean I can reach into the 1500 for the values of the counters and display them on the touch screen?

Could I also somehow have the operator key in a number that the counter should theoretically get after running a certain amount of gallons though and have the PLC do the math to calculate a percentage or do some math to find out how far off the meter is? I have been though some heavy duty PLC classes but it is still somewhat new to me

Thanks

Bill

Your are correct. The Micrologix 1500 base unit only supports 2 High Speed Counters so you will have to use a HSC expansion module to do 4.

For a simple application I would suggest getting a Panelview that supports DF1

From that point the user input you are wanting shouldn't be a problem

High-speed capabilities is exactly what makes difference among PLC brands.
Allen Bradley MicroLogix/SLC does not fit this application.
I would simlpy use another brand, something like Omron or Mitsubishi.

And how do they fit the application better?

In fact I just did some looking and the Micrologix to the Misubishi are apples to apples in that size Plc. There both good but don't see anything better about eithers High Speed Counters

Whats special about the Omron?


But I just got thinking about it and BadgerGuy says that wants to kick some solenoid when it hits 100 gallons. If that pumps through something other than the flow switch then you don't have to sense direction and only need one input per flow switch. If this is true you can use the Micrologix 1200 base unit. Inputs 0-3 can count at 20 kHz. The Micrologix 1500 could do 8 flow switches. And yes the Misubishi can do it too but I still want to know what is so special about them

How about the recent micrologix 1100 processor. High speed counter, analog in, ethernet, and small built in LCD. Looks to be a nice little unit, and I am condsidering one for a similar project using flowmeters and looking for feedback on them.

Yes it will do the application. We probably have 40 to 50 of Micrologix and the Misubishi FX2Ns doing High Speed Counter Applications here. And last time I check the AB was doing it over 10 years ago too.

But you still didn't say how they do it better.

The Misubishi's inputs will count a little quicker, but in a harsh industrial environment to Outputs don't quit hold up as well. They don't seem to have the life of the ab outputs

On the other hand the AB inputs are not as noise tolerant but their software is much better and much easier to integrate into the plant network

I could go on and on but Mistubishi and Ab Plcs are Apples to Apples in funtionality on the small Plc Base.

So how is changing to the Mishubishi going to help him with its problem. It's the equivalent of changing from a Ford to a Chevrolet.

I realize that people from AB forum will not like this, but Mitsubishi FX series beats the MicroLogix in everything except for the programming software.
Working in automation over 15 years, I have often seen AB hardware out of order and never Mitsubishi.
And not mentioned but important- ML lack of online programming is a defficiency that cannot be compensated by any other advantage (if any).

"So how is changing to the Mishubishi going to help him with its problem"-
The answer is simple: 4 to 6 high-speed counters on Mitsu vs 1 to 2 ones on ML.

Actually the Ab is 4 or 8 High Speed Counters so I'm still not sold.

I agree the lack of online edits is a definate downfall on the Micrologix and there are many more and the Misubishi has just as many.

We have had failures of both. The micrologix major problem is its lack of noise sensitivity on its inputs and the fact that if you short out its 24DVC it can cause the program to be losted. The Misubishi is that its outputs ar not as rugged. We have many failures of them especially on frequent pulsing of our hydraulic valves

I use micrologix 1000s. They have 4 high speed inputs, but only one hardware HSC. Do the 1200/1500 actually have 4 high speed hardware counters built in?
Thanks
Paul C.

The Micrologix 1200 Input 0-3 are capable of high speed counting up to 20 kHz. Inputs 4-23 are capable of high speed counting up to 1 kHz with a catch. They are scan time dependant. Our typical program scan is 2.5 to 3.5 milliseconds so I usually use 5 milliseconds as a rule of thumb. So I will only use inputs 4-23 for counting of 200 Hz or less

The Micrologix 1500 Input 0-7 are capable of high speed counting up to 20 kHz. Inputs 4-23 are the same as the 1200 and are also scan time dependant.

None of our Micrologix 1000s are doing high speed counting and I have never used one of them in that type of application so I’m not sure about them

When you say 1 high speed counter for the 1200 and 2 for the 1500 I believe you are referring to the function file method of counting. This is only one method. BadgerGuy said the Plc was new to him so wasn’t going to get into details the other methods. The HSC function file is much easier. You can use the Micrologix 1200 for 4 single directional counters and 2 bidirectional counters. The Micrologix 1500 can be used for 8 single directional counters or 4 bidirectional counters.

We are talking high-speed counters here, counting in scan is out of the scope.
What good is 8 inputs capable of high speed counting up to 20 kHz while only two high-speed counters are supported?

Only the upper inputs 4-23 on the 1200 and 8-23 on the 1500 are scan dependant. The function files are only an easy way to use the counters, not the only way. They make them easy to configure, turn outputs on at certain times, etc. There are only 1 of them on the 1200 and 2 of them on the 1500.

We have a machine that has a 1200 on it and used the first 4 inputs for counters at a rate of a little more than 12 kHz so I know that you can use these inputs for counter. This isn't some theory to argue. The machine has ran for 3 years like this.

So can you share the code?
I think many of us would appreciate it.

You argue with me saying AB would make a product capable of physically counting with 4 inputs but only capable of counting with 2 in the software and now you want me to show you how.

If you had asked this question earlier instead of insisting that it could only count with two and trying to tell how every other Plc could do it better when it was obvious that you were not that familiar with the product I would post some code.

But I’m going to have to say go get yourself some books and write your own

This is just an excuse. You could prove yourself better (and ashame me better) by providing such code. I do not need it for real life- our company is an OEM and fortunately we choose our PLC brand. God save us from MicroLogix.
And remember, we are talking of formal high-speed counters, not software gimmics like a "refresh and count" subroutine being called many times during a scan or similar.

Ok this whole post got me curious of the true counting capablities of the Micrologix so I set up a test. The max motor rpm of my test limited my testing to 13373 Hz.

I used a Controllogix M02AE as a control and tested a Micrologix 1200.

Inputs 0-3 had the same values as the Controllogix at a rate of 13373 Hz

Since inputs 4-23 are scan time dependant I made the program address all 24 inputs and setup a sequencer to fire all 16 outputs so the results should be realistic. Although Inputs 4-23 have a resolution of 1kHz the fasted rate I could get with it was 556 Hz. Thats about half of the physical capablility of the inputs but still not bad. I could probably strip the program down and hit 1kHz but these are probably pretty realistic since I am addressing all of the physical I/O.

Ok, for inputs 4-23 these are expected numbers with regular counters and scan time in 1ms neighborhood.
But it is still unclear what was the counting method for inputs 0-3 and whether all they were counting simultaneously.

Sergie,

Look at page A-2, Table A2

Done.
Nothing new. Absolutely confirms whatever I said before and does not answer my last question.

I wasn’t going to reply to this post anymore but I had one of these Micrologixs that don’t work on a machine here that we pulled out while they are doing some work on the hydraulics and decided to play a little more. I put 3 encoders inline on it. The first is a 1000 count going to a Controllogix. The second one is also a 1000 count encoder and I put Channel A on Input 0 of the Micrologix and Channel B on Input 2 of the Micrologix. The third is a 600 count encoder and I put Channel A on Input 1 of the Micrologix and Channel B on Input 3 of the Micrologix. I didn’t have 480 VAC to run the motor off of so this does not test the max frequency of the counters but I did turn it faster than one revolution per second. So this definitely gets us above the 1000 Hz limit of inputs 4-23 and out of the range of using normal program scan to do it.

I stopped the Controllogix at 635367 counts. Input 0 was at 635368. Input 1 was at 381221. Input 2 was at 635367. Input 3 was at 381220.

Yes none of the counters have the exact same value but they are plus or minus one pulse which I would account to the encoders not being exactly lined up the A being a half of pulse off of the B.

Also did some calculations since I can’t hit the 20 kHz with any of the machines we have and you probably could not hit the 20 kHz. It is probably closer 19700 Hz give or take 500 Hz. While it is not scan time dependant it is processor dependant. You probably could hit the 20 kHz with the 1500 but I did not do the calculations.

Mickey did point you in the right direction but not quite the right book. But if you do a little reading in that book it references the book you need to do it.

If you are serious about learning how to do this with the Micrologix and not just trying to say how everything else is better, do a little reading in these books. Once you find a little more information on how to do it ask some specific question and I will be glad to help you understand it. I you aren’t serious just keep blabbering on the way you have been.

This is my last post on this matter

So many words and so little information. Even not mentioned the ML model.
And again, was it really HIGH-SPEED counters?

I can solve this application with MicroLogix without reading manuals.
Actually, I can do it in more than one way, even without HSCs at all.

But you have not prooven that there are more than 2 HSCs in ML.
Just try to specify HSC:2 in a device name. Only this is a formal HSC.

I do not expect you to reply.
If the author of the thread still needs help, I will gladly guide him to the most cost-effective solution.

BTW, where are the AB experts?
Judge us, please!

Any chance of putting aside the my brand is better than your brand squabble and post some code so myself and others could perhaps learn some new programming techniques?

I love it, a good flame war here on MrPLC.com!

Forget A-B vs. whatever, my Atari 800 is way better than your Commodore 64!!